Described herein are aspects generally related to communication systems, and more particularly, to processing reference signals transmitted in a wireless communication system.
Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, multimedia, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and others. These systems are often deployed in conformity with specifications such as Third Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), Ultra Mobile Broadband (UMB), Evolution Data Optimized (EV-DO), Institute of Electrical and Electronics Engineers (IEEE), etc.
In cellular networks, “macro cell” base stations provide connectivity and coverage to a large number of users over a certain geographical area. A macro network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in poor user experience. In addition, the macro cells may not be able to sufficiently accommodate radio resources for a high number of users.
To improve indoor or other specific geographic coverage, such as for residential homes and office buildings, and/or to offload network traffic from macro cells, additional “small cell” base stations, typically operating at a lower power than the macro cell base stations, have been and are being deployed to supplement conventional macro networks. Small cell base stations may also provide incremental capacity growth, richer user experience, and so on. Additionally, in LTE, small cells have been extended into the unlicensed frequency spectrum such as the Unlicensed National Information Infrastructure (U-NII) band used by Wireless Local Area Network (WLAN) technologies. This extension of small cell LTE operation is designed to increase spectral efficiency and hence capacity of the LTE system. This can also result in multiple small cells relating to multiple public land mobile networks (PLMN) operating on the same frequency.
Presently, devices configured to communicate with such small cells in unlicensed frequencies may not be able to distinguish an underlying PLMN of each the small cells, and thus may attempt to establish communications with one or more small cells outside of a current PLMN associated with the device. This may result in failed attempts by the device to handover to a small cell belonging to a different PLMN, to add secondary cell carriers (e.g., in carrier aggregation) belonging to a different PLMN, etc., as well as measurement of cells to which the device may not be able to handover or add a carrier.